We have initiated studies of the genetic basis for differences in pain perception and response in collaboration with scientists at the NIDCR and at Hebrew University in Israel. We are studying human subjects who have experienced traumatic limb amputation, evaluating associations of genetic variants with risk of phantom limb pain. We are also evaluating a mouse model of pain known as autotomy. The latter work involved our development of new statistical methods suitable for the robust analysis of categorical data obtained in the recombinant inbred strain breeding design. Both human and animal studies have resulted in findings that implicate specific chromosomal regions and candidate genes which are located in these regions that are thought to be involved in mediating pain perception and response. Further studies to follow up on these findings include additional breeding studies in the mouse model and evaluations of additional human subjects.